This invention relates to process and apparatus for recovering clean fiberglass and resin from resin treated waste fiberglass. More particularly, it relates to improvements in such a process and apparatus in which the resin is urea formaldehyde.
In his U.S. Pat. No. 4,300,955, Yount recognized the shortcomings of the then practice of disposing of waste fiberglass including the resin in landfills. Thus, as he points out, this results in the loss of valuable fiberglass as well as recovery of the resin, such as urea formaldehyde, for subsequent use. Thus, he proposed a process for separating the resin from the treated fiberglass by passing it though a treatment tank containing a mixture or solution of between ten percent and fifty percent phosphoric acid (H3PO4) to water (H2O) which is heated to approximately 200 degrees Fahrenheit. The waste product is allowed to remain in the tank between five and thirty seconds or until the resin has been removed from the fiberglass fibers. The product is then removed from the treatment tank and washed with water.
The system is very cumbersome to operate and is not believed to be economically feasible from the standpoint of what is necessary to transfer material from one state of the process to the next, and it is the object of our invention to accomplish Yount""s purposes with a process and apparatus which not only minimize the amount of effort and time required, but also promote separate of the waste fiberglass into the components for reuse, as above mentioned.
Thus, in accordance with our invention, the waste fiberglass is separated into clean fiberglass and resin, whereby both are recovered in substantially less time and with less effort. In a continuous batch tunnel machine of the type traditionally sed for washing goods, and more recently used in the recovery of fiber, as shown and described in U.S. Pat. No. 5,225,045. Thus, the machine comprises end to end modules in each of which a perforated basket is rotatable and of such construction as to transfer the goods within each basket to subsequent baskets and out the end of the basket at the exit of the machine. As the waste fiberglass is introduced into the basket at the entrance to the machine, and caused to move through the machine from basket to basket, it is agitated to promote separation of the resin from the waste fiberglass. More particularly, while so traversing the machine, the fiberglass is treated with acid and wash loops which circulate through the basket in a manner to quickly and efficiently separate waste fiberglass for recovering then clean fiberglass and resin suitable for further use.
Thus, an acid loop is established by introducing a solution of phosphoric acid and water into a module downstream of the entrance for counterflow through the fiberglass in the modules upstream thereof as the fiberglass is transferred from basket to basket in a downstream direction, collecting the solution from the modules through which it flows, cooling the collected solution and passing the cooled solution into a clarifier in which the sludge of resin is separated and collected for recovery therefrom, and heating the solution upon separation from the resin. Water and phosphoric acid are then added to the heated solution to return it to essentially its original concentration, and the solution, as reconstituted, is introduced into the downstream module for recirculation through the acid loop.
As the fiberglass continues to be transferred from module to module and out the exit of the machine, a water loop is established wherein the fiberglass so transferred is washed in water before discharge from the exit of the machine. The water is circulated through at least one of the modules and into a clarifier in which residual resin is separated for recovery from the water, and from which the clarified water is reintroduced into the module for recirculation back through it.
In the preferred and illustrated embodiment of the invention, the solution is comprised of water with approximately a ten percent concentration of phosphoric acid, and the resin in the waste fiberglass is urea formaldehyde.
As also illustrated, and in preferred embodiments of the invention, a solution in the acid loop is drained from a module downstream of the module into which it is introduced for return to the tank of the acid loop for collection.
As further illustrated, the solution from the clarifier is passed into the module at the entrance to the machine along with the waste fiberglass.